Novel fluorinated aliphatic triethers

ABSTRACT

PERHALOISSOALKYL ETHERS OF A,W-PARTIALLY-FLUORINATED ALIPHATIC ETHER DIOLS USEFUL AS STABLE FLUID DIELECTRIC COOLANTS INERT LIQUID MEDCIA FOR CARRYING OUT CHEMICAL REACTIONS, HYDRAULIC FLUIDS, LUBRICANTS AND AS OXYGEN AND CARBON DIOXIDE TRANSPORT COMPONENTS OR ARTIFICIAL BLOOD COMPOSITIONS.

United States Patent "i e 3,739,033

Patented June 12, 1973 3,739,033 lz oR NOVEL FLUORINATED ALIPI-IATIC TRIETHERS Louis G. Allen, Grchard Park, and Richard F. Sweeney wherein R alnd R are llke or unlike radicals of the Elma, N.Y., assignors to Allied Chemical Corporation, formula New York, N.Y. No Drawing. Filed Mar. 1, 1971, Ser. No. 120,065 5 R1 Int. Cl. C07c 43/00 US. Cl. 260-615 F 10 Claims ABSTRACT OF THE DISCLOSURE 10 FCOCF2( 2)m( 2)n Perhaloisoalkyl ethers of or,w-partially-fluorinated ali- K] phatic ether diols useful as stable fluid dielectric coolants, 0F inert liquid media for carrying out chemical reactions, hy-

draulic fluids, lubricants and as oxygen and carbon dioxide transport components of artificial blood composiwherein tlons.

(i) R R R and R independently at each occurrence are fluorine, chlorine or perhaloalkyl, or one of R CROSS-REF TO RELATED and R and one of R and R when taken together, are

APPLIC perhaloalkylene groups forming a homocyclic aliphatic (l) Copending US. application of Louis G. Anello, Structure of from 4 i0 Carbon atoms, which R1 :R4 Richard F. Sweeney and Morton H. Litt, Ser. No. 818,- groups y have r m 1 to 9 carbon atoms and WhlCh 832, fil d A 23 1969, titl d POlYHuoroisoalkoXy. halo substituents thereof are fluorine or chlorine, with alk l H fid now b d d the provlso that no more than three of the R R groups (2) Copending US. application of Louis G. Anello, p e y p Richard F. Sweeney and Morton H. Litt, Ser. No. 721,- 25 X, Which y be the Same o d fi t 1n dlfier n 113, filed Apr. 12, 1968, entitled Terminally Unsaturated z groups, 15 y g 0r fluOIlne Fluoroolefins now US. Pat. 3,577,465. 1) m 1s 0 to 38 3 Copending US. application of Louis G. Anello, his aninteger of 1 M2 Richard SWeeIleY and Morton LIVE, Q- 721," The critical structural features of the present novel P 12, 1968, entltied Fillofeeafhon Acids and compounds are considered to be the three ether oxygen D r1 at1V substituents, the two terminal fluorinated perhaloisoalk- BACKGROUND OF THE INVENTION oxy groups each attached to a difluoromethylene radical, and the two non-fluorinated methylene radicals to which the central ether oxygen is bonded.

The present compounds are readily prepared by known reaction techniques from the corresponding fluorinated perhaloisoalkoXy-fluoroalkyl iodides, alcohols or alkali metal alcoholates.

Symmetrical ethers of the invention, that is ethers of This invention relates to novel aliphatic polyethers and more particularly to novel polyfluorinated aliphatic triethers. It is especially concerned With a novel class of perhaloisoalkyl ethers of partially fluorinated a,w-a1iphatic ether diols.

Recent development in the electrical and space indus- 4O tries have intensified the need for dielectric coolant fluids the above Structural formula wherein RIZR, are com for miniaturized Packages of hefiiseiijsiiive eieciroiiic veniently prepared according to known reaction techniques components. For such purposes, dlelectrlc fluld coolants b reaction (Equation 1 f oleum with the perhaloisowhich h electronic winpoilents g be immersed are alkoxy-fluoroalkyl iodide (I) followed by acid hydrolysis highly desirable- Such fluids in addition I being good (Equation 2) of the resultant sulfuric acid half ester (11) i f agents, P exceptwnally goofi to the corresponding alcohol (III) and intermolecular eieeirlefll Insulating P p Such as high dieieciiic acid-catalyzed dehydration (Equation 3) of the latter to strengths and volume resistivities and low dissipation facf the desired ethen tors and dielectric constants. Such coolants should also be stable as fluids over a wide temperature range and Equation 1 (RIZRII has the meaning given above) should be non-toxic, non-flammable and non-explosive.

In the past, such requirements have been met at least pard -F oleum REOSOflH 1/21;

tially by fluorinated perhalogenated ethers which have (I) (II) provided dielectric coolant systems of lighter weight and Equation 2 (RfZRfi has the meaning given above smaller volume than prior art non-fiourinated fluids. While such fluorinated perhaloether fluid coolants have proved of greatvalue, their application has been limited H+ RrOSOaH H O RgOH H 80 by the relatively few different structural classes of fluori- (n) i nated perhalogenated ethers which are available and by Equation 3 iRf=Rff has the meaning given above) the tendency to even greater miniaturization of electronic Ht equipment and higher efliciency requirements. ZROH H2O It is the object of the present invention to provide a (In) novel class of fluorinated aliphatic triethers.

It is another object of the invention to prepare novel The conversion of the iodide to the corresponding table dielectric coolant fluid alcohol (III) via the corresponding sulfuric acid half- These and other objects and advantages will be apparester according to Equations is carried out by ent from the following description of our invention, treating the iodide With about 20-25% oleum at about SUMMARY OF THE INVENTION to C., and thereafter diluting the initial reaction mixture containing the aforementioned sulfuric acid ester The above objects are attained according to the inven- With water to provide a sulfuric acid concentration of tion in a novel class of fluorinated aliphatic triethers of 70 about 35-80 weight percent and heating the diluted mass the structural formula at about 100-105 C. to obtain the alcohol (III) in substantial record with the procedure of British Pat. 994,607 issued June 10, 1965. The desired ether which is formed as a by-product of the reaction of Equation 2 via the intermolecular dehydration of the alcohol (III) in accordance with Equation 3 above, can be readily separated from the alcohol and the other constituents of the crude reaction mass by conventional means, for example fractional distillation, under diminished pressure. The recovered alcohol can be reacted with additional aqueous sulfuric acid to form additional amounts of the desired ether in accord with Equation 3. The intermolecular dehydration of aliphatic alcohols to the corresponding ethers in the presence of a sulfuric acid catalyst is a conventional technique which is disclosed in Rodds Chemistry of Carbon Compounds, section edition, Elsevier Publishing Co., New York, 1965, volume I, Part B, page 47.

The novel triethers of the invention can also be prepared by reaction of the aforementioned fluorinated perhaloisoalkoxyfluoroalkyl iodides (I) with the alkali metal salts (IV), that is alkali metal alcoholates, of the aforementioned fluorinated perhaloisoalkoxy fiuoroalkyl alcohols (III) according to the reaction of Equation 4 below. This conventional procedure can be used to prepare either symmetrical or unsymmetrical ethers of the invention.

Equation 4 (R; and R have the meanings given above, M is cation of an alkali metal) R I RfORff+ This technique, which involves heating the iodide (I) and alkali metal alcoholate (IV) in liquid organic medium, is disclosed in Carter et al. U.S. Patent 1,459,177, issued June 19, 1923.

Both symmetrical and unsymmetrical ethers of the invention are also prepared by reaction of an alkali metal salt (V) of the aforementioned sulfuric acid half ester of the fluorinated perhaloisoalkoxy fiuoroalkyl alcohol and the alkali metal salt (IV) of such alcohol according to Equation 5 below.

Equation 5 (R Rff and M have the meanings given above) This preparatory technique, which is also old in the art, is disclosed in Rodds Chemistry of Carbon Compounds, ibid.

The fluorinated perhaloisoalkoxyfluoroalkyliodides which are utilized in the foregoing procedures to prepare the novel ethers of the invention correspond to the struc tural Formula VI below.

wherein R R R and R m and n have the meanings given above.

The iodide intermediates are prepared by condensation, that is telomerization, of a telogen iodide of Formula VII below with a telomerizable olefin seelcted from the group, ethylene, tetrafiuoroethylene and vinylidene fluoride.

R4 (VII) wherein R R R and R have the meanings given above and r is 1 to 2.

Telogen iodides of Formula VII wherein r is 2 are disclosed in Litt et al. U.S. Patent 3,453,333, and in Evans et al. U.S. Patent 3,470,256.

Telogen iodides of Formula VII wherein r is 1 are prepared from the aforementioned telogen iodides of Formula VII wherein r is 2 by liquid phase reaction with sulfur trioxide at 50175 C. to replace the iodide substituent with the radical COF, hydrolysis of the resultant acyl fluoride to the corresponding carboxylic acid, neutralization of the resultant carboxylic acid with alkali-free silver oxide and finally iodination of the resultant silver carboxylate to form the desired telogen iodide of Formula VII wherein r is 1.

The aforementioned telomerization of telogen iodides of Formula VII, which may be effected stepwise employing different telomerizable olefins in the various steps, is carried out in accordance with the procedure described by Anello et al. U.S. Patent 3,514,487, issued May 26, 1970. Telomerization reactions involving vinylidene fiuoride provide two telomerization products or telomers, namely a principal telomer product wherein the alkyl residue of the telogen iodide is attached to the methylene group of the telomer and the iodide of the telogen is attached to the difluoromethylene group of the product and a minor product wherein the alkyl residue of the telogen is attached to the difiuoromethylene group in the telomer and the iodide residue of the telogen is attached to the methylene group of the telomer, which products are readily separated by conventional techniques.

As will be apparent to those skilled in the art only telomer iodide products terminating in the -CH I moiety can be used directly in preparing the novel ethers of the invention according to the reactions of Equations 1-4 above. However, telomer iodides of the aforementioned telomerization reactions which terminate in CF I moieties can, by the following synthetic routes, be converted to the desired iodide starting materials of Formula VI or can be converted to alcohols of Formula III above which can, in turn be converted directly to the present novel ethers.

Telomer iodides terminating in the moiety --CF CF I are treated with sulfur trioxide to convert the CF CF I group to the CF COF group, followed by alcoholysis of the CF COF group to CF COOCH and subsequent LiAlH reduction of the latter group to CF CH OH. The resultant alcohol can be used directly in preparation of the present ethers according to the reaction of Equation 3 above. Alternatively the CF CH OH group of the alcohol is reacted conventionally with p-toluenesulfonyl chloride to form the corresponding OFzCHzOSOz-CHa group which by known reaction with alcoholic alkali metal iodide is converted to the desired -CF CH I substituent. The aforementioned conversion of -CH CH I moieties to CF CH OH groups is disclosed in Canadian Patent 852,256 issued September 22, 1970. The foregoing procedure for converting primary aliphatic alcohol groups, such as -CF CH OH, to the corresponding alkyl iodide groups, such as -CF CH I, by reaction with p-toluene sulfonyl chloride and conversion of the resultant p-toluenesulfonate ester group to an alkyl iodide moiety, is disclosed in Method 208, Lovelace et al. Aliphatic Fluorine Compounds, Reinhold Publishing Corporation, 1958, page 42. The foregoing reaction sequence is also utilized to convert the telogen iodide represented by (VII) wherein r is 2 to the corresponding iodide starting material represented by Formula VI wherein m is 0 and n is 1 which iodide product can also be employed as a telogen iodide in the aforementioned telomerization reactions.

Telomer iodides terminating in the group CH CF I are treated with alcoholic alkali metal hydroxide to remove hydrogen iodide to form the moiety CH=CF The latter group is oxidized by alkali metal permanganate or dichromate to form the group -COOH which is esterified and reduced to the group -CH OH with lithium aluminum hydride. The resultant alcohol can be converted directly to the ethers of the invention according to the reaction of Equation 3 above. Alternatively the CH OH group of the alcohol is converted to CH I by reaction with p-toluene sulfonyl chloride and subsequent reaction of the resultant p toluenesulfonate ester group with alcoholic alkali metal iodide according to the aforementioned conventional procedure of Lovelace et al. The conversion of the COOH group to CH OH via conventional esterification and LiAH reduction of the resultant ester is more particularly described in the aforementioned Canadian Patent 852,256.

In preferred compounds of the invention as delineated by the above general formula, R, and R are like radicals, m is at least 1 or n is 2. Still preferably when m is 1, R R R and R are fluorine, perfluoroalkyl radicals or one of R and R and one of R and R when taken together, are perfluoroalkylene groups forming a homocyclic aliphatic structure.

An especially preferred class of ethers of the invention correspond to the structural Formula VIII below wherein x is an integer 1 to 20 and y is an integer 2 to 20.

The particularly preferred novel ethers of Formula VIII wherein y is an integer 3 to 20 are conveniently obtained from a perfluorinated isopropoxy alkyl iodide (IX), prepared as described above, by condensation with a terminally unsaturated aliphatic alcohol (X) in the presence of a catalyst such as alpha, alpha-azobisisobutyro nitrile in accord with Equation-6 below to form a fluorinated isopropoxy-iodoalkyl alcohol (XI) followed by reductive deiodination of the latter product with a suitable reducing agent such as LiAlH to form the corresponding iodine-free alcohol (XII) according to Equation 7 below. The latter alcohol (XII) is readily converted to the desired preferred ether (XIII) by acid-catalyzed intermolecular dehydration in accord with the reaction of Equation 3 above.

Equation 6 (x has the meaning given above and y is an integer of 3 to 20) (C F9101?0(oF, ,.oH,oH(oH,) ,oH

(XI) 1 Equation 7 (x has the meaning given above and y is an integer 3 to 20) The foregoing reactions of Equations 6 and 7 are more particularly described in aforementioned Canadian Patent No. 852,256.

The novel fluorinated aliphatic triethers of the invention are heat transfer agents having exceptionally good electrical insulating properties such as high dielectric strength and volume resistivity and low dissipation factor and dielectric constant. The present ethers are also stable as fluids over wide temperature ranges. The foregoing properties render these novel compounds particularly use ful as dielectric liquid and/or vapor phase coolants for heat sensitive electronic apparatus, particularly in such coolant systems which are exposed to environmental conditions of extreme high and low temperatures. Moreover, the present novel ethers are useful as hydraulic fluids; dielectric media; lubricants; inert liquid media for carrying out chemical reactions, particularly reactions of fluorocarbons; and as oxygen and carbon dioxide transport components of artificial blood compositions of the type disclosed in Chemical and Engineering News, vol. 48 (May 18, 1970) pages 30-31.

In the following examples which serve to illustrate our invention, percentages and proportions are by weight unless otherwise noted and temperatures are in degrees centigrade. EXAMPLE 1 A reaction flask is charged with 9000 g. of 20% oleum. With vigorous agitation, 3000 g. (6.83 moles) of are added over a 45-minute period as the oleum is heated from 25 to 77. Heating is continued for 1 hour at 100. To hydrolyze the intermediary hydrosulfate, 8000 g. of 48% H 50 are charged to the reaction mixture to give a final sulfuric acid content of 75%. The mixture is heated to for 8 hours. The water-insoluble oil which separates is decanted, washed with 10% aqueous sodium metabisulfite to remove elemental iodine, dried and fractionally distilled to give 37 g. (0.084 mole) of (CF CFOCF CF CH CH I, B.P. 138140/760 mm., 1081 g. (3.28 moles) of (CF CFOCF CF CH CH OH B.-P. 5254/l0 mm., 443 g. (0.69 mole) of the desired product, bis-(1,1,2,2 tetrahydrotetrafluoro 4 heptafluoroisopropoxybutyl)ether, B.P. 82-84/4 mm. and 530 g. (0.73 mole) of [(CF CFOCF CF CH CH O] 80 B.P. -l34/ 3 mm. The triether product has a freezing point of 74, a density of 1.60 g./cc. at 25, a dielectric strength of 12.2 kv./ 0.1 (according to the method of ASTM-D877); a dielectric constant of 3.37 at 1 kc. (according to the method of ASTM-D-ISO); a dissipation factor of 0.00021 at 1 kc. (according to the method of ASTM D-); and a volume resistivity of 'I7).78 10 ohm-cm. (according to the method of ASTM- Infrared and nuclear magnetic resonance spectrograph analyses of the triether product are consistent with the following structural formula Analytical data: Calcd. for C F H O (percent): C, 26.17; F, 65.19; H, 1.25; S, none; I, none. Found (percent): C, 25.49; F, 63.68; H, 1.35; S, none; 1, none.

EXAMPLE 2 In substantial accord with the procedure of Example 1, 2758, g. (5.07 moles) of (CF CFO(OF CF CH CH I is charged over an 80 minute period to 7200 g. of 20% oleum which is agitated at 90 to 100 during the addition.

The reaction mixture is stirred for 1.5 hours and is then cooled to room temperature. This crude mixture is slowly added to 16,000 ml. of water containing 1050 g. of Na S O and the mixture is maintained at 100 for 4 hours to remove elemental iodine. The water-insoluble oil which separates is decanted, dried and fractionally distilled under diminished pressure to give 158 g. 0.29 mole) of (CF CFO(CF CF CH CH I, B.P. 72-75/ 15 mm., 1394 g. (3.24 moles) of (CF 3 CFO (CF CF CH CH OH B.P. 61-33/4 mm. and 77 g. (0.91 mole) of the desired product, bis-(1,1,2,2-tetrahydro-octafluoro-6-heptafiuoroisopropoxyhexyl)ether, B.P. 100102/ 1 mm.

Infrared and nuclear magnetic resonance spectrographic analyses of the product are consistent with the following structural formula Analytical data: Calcd. for C F H O (percent): C, 25.61; F, 67.62; H, 0.95; I, none; S, none. Found (percent): C, 26.10; F, 67.24; H, 0.84; I, none; S, none.

EXAMPLE 3 In substantial accord with the preparatory procedure of Example 1, 2724 g. (4.25 mole) of is charged over a period of 75 minutes to 7200 g. of 20% oleum maintained with vigorous agitation at 85- 95 during the addition. The reaction mixture is stirred for 90 minutes and is then cooled to room temperature. This crude mixture is slowly added to 16,000 ml. water containing 1050 g. Na S O and the mixture is maintained at 100 C. for 4 hours. The water-insoluble oil which separates is decanted, dried and fractionally distilled to give 114 g. (0.18 mole) of (CF CFO(CF CF CH CH I B.P. 7879/4 mm., 1485 g. (2.8 moles) of (CF CFO( CFgCFz CH CH 0H,

B.P. 8081/4 mm. and 57 g. (0.064 mole) of the desired product, bis- 1,1,2,Z-tetrahydrododecafiuoro-8-heptafluoroisopropoxyoctyl)ether, B.P. 138l40/1 mm.

Infrared and nuclear magnetic resonance spectrographic analyses of the product are consistent with the following structural formula Analytical data: Calcd. for C F H O (percent): C, 25.35; F, 69.02; H, 0.76; I, none; S, none. Found (percent): C, 25.78; F, 69.54; H, 0.72; I, none; S, none.

EXAMPLE 4 To a 300 ml. 3-necked flask containing 102 g. 96% sulfuric acid is charged 100 g. (0.31 mole) of (CF 3 CFOCF CF CH CH OH On addition of the alcohol the temperature of the mixture rises rapidly from about 30 to 55. The mass is then heated with agitation to 100 and maintained at the latter temperature for two hours. After addition of 50 g. of water to provide a sulfuric acid concentration of about 72% in the mixture, the mass is heated at 110-115 for two hours and cooled to room temperature. The waterinsoluble oil which separates as the lower layer of the mass is decanted, washed with water, dried and fractionally distilled under diminished pressure. There is recovered 80 g. (0.24 mole) of unreacted B.P. 50/10 mm., 3.15 g. (0.005 mole) of the desired product, bis-(1,1,2,2-tetrahydrotetrafluoro 4 heptafluoroisopropoxybutyl)ether of Example 1, B.P. 84/ 3 mm. and 16.4 g. (0.026 mole) of (CF CFO CF CF CH CH O] 50 B.P. 115/1 mm.

By the synthetic technique of Example 1, the following the corresponding fluorinated isoalkoxyalkyl iodides:

I I CFa CF By the synthetic technique of Example 4 the following additional ethers of the invention can be prepared from the corresponding fluorinated isoalkoxy alkyl alcohols.

By the technique of the reaction of Equation 4 above the following unsymmetrical ethers of the invention can be prepared in accordance with the general equation We claim: 1. Compounds of the formula r' i-oomoxnuonnr 10 wherein (i) R R R and R independently at each occurrence are fluorine, chlorine or perhaloalkyl, or one of R and R and one of R and R when taken together, are perfluoroalkylene groups forming a homocyclicaliphatic structure of from 4 to 6 carbon atoms, which R -R, groups may have from 1 to 9 carbon atoms and which halogen substituents thereof are fluorine or chlorine with the proviso that no more than three of the R -R groups are perhaloalkyl groups (ii) X, which may be the same or different in different CX groups, is hydrogen or fluorine (iii) ml is 0 to 38 (iv) n is an integer 1 or2 2. Compounds as claimed in claim 1 wherein R, and R are like radicals.

3. Compounds as claimed in claim 1 wherein m is at least 1.

4. Compounds as claimed in claim 1 wherein n is 2.

5. Compounds as claimed in claim 3 wherein R R R and R are fluorine, perfluoroalkyl radicals of 1 to 9 carbon atoms of one of R and R and one of R and R when taken together, are perfiuoroalkylene groups form- 5 ing a homocyclic aliphatic structure.

6. Compounds as claimed in claim 1 having the forwherein x is an integer 1 to 20 and y is an integer 2 to 20.

7. A compound as claimed in claim 6 having the formula [ (CF CFOCF CF CH CH O 8. A compound as claimed in claim 6 having the for- 9. A compound as claimed in claim 6 having the formula 10. A compound as claimed in claim 2 having the formula (CF CFOCF CH 0 References Cited UNITED STATES PATENTS 3,549,711 12/1970 Merrill et a1 260-615 R 3,420,793 1/ 1969 Pittman et a1. 260-615 R X 3,435,078 3/ 1969 Nychka et al 260615 R 3,637,868 1/ 1972 Nychka 260-615 R 2,824,141 2/ 1958 Zisman et a1 260-615 R 2,831,033 6/1958 ORear 260615 R X OTHER REFERENCES Weinmayr: J. Org. Chem., 28 (1963), pp. 492-494.

HOWARD T. MARS, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 139 33 Dated June 12 1973 Inventor(s) .Louis G. Anello and Richard F. Sweeney It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1, line 60 "even" should read ever Col. 3, line 1 record" should read accord Col. 3, line 1 "99,607" should read 99 M607,

Col. 3, line 15 "section". should read second Col. 4, first formula that part which reads "-O(CF )I I Q should read O(CF ,I

Col. 7, line 68 "B.P. 50 should read B.P. 5 4

Col. 8, line 12 that part of the formula which reads "2(CF )CFO" should read 2(CF CFO Col. 10, line 6, "atoms," should read atoms Col. 10, line 23 "atoms of" should read atoms or Signed and sealed this 9th day of Jul} 197i.

(SEAL) Attest:

MCCOY M. GIBSON, JR. 0. MARSHALL DANN Attesting Officer Commissioner of Patents F ORM PC4050 (10-69) USCOMM-DC 6O376-P6D uus. GOVERNMENT nmmuc orncz; nu o-ass-au 

